As described in detail in my aforesaid prior filed U.S. patent applications, many suggestions have been made in the prior art for producing three dimensional motion pictures. Many prior art methods and apparatus have suggested the use of multiple recording cameras separated by a lateral lens distance to obtain right and left recorded film frame views of the scene, with subsequent projection of left and right film frame views in alternating sequence onto a receiving surface for visualization. Many of such prior art attempts also required multiple projectors and auxiliary apparatus positioned between the eyes of the observer and the surface onto which the scenes were projected, e.g., differently colored or polarized glasses to be worn by the observer, or complicated moving shutter systems positioned between the projector or observer and the screen surface being observed.
Prior art patents relating to three dimensional photography which have been developed and made of record in prosecution of my aforesaid prior patent applications are identified as follows:
______________________________________ U.S. Pat. No. 765,980 U.S. Pat. No. 2,792,745 U.S. Pat. No. 1,265,352 U.S. Pat. No. 2,860,562 U.S. Pat. No. 1,307,074 U.S. Pat. No. 2,891,440 U.S. Pat. No. 1,351,508 U.S. Pat. No. 2,938,425 U.S. Pat. No. 1,394,797 U.S. Pat. No. 2,952,182 U.S. Pat. No. 1,435,520 U.S. Pat. No. 2,996,949 U.S. Pat. No. 1,488,027 U.S. Pat. No. 3,006,241 U.S. Pat. No. 1,927,925 U.S. Pat. No. 3,178,720 U.S. Pat. No. 1,939,343 U.S. Pat. No. 3,186,002 U.S. Pat. No. 2,011,353 U.S. Pat. No. 3,240,549 U.S. Pat. No. 2,022,454 U.S. Pat. No. 3,324,760 U.S. Pat. No. 2,080,604 U.S. Pat. No. 3,366,438 U.S. Pat. No. 2,101,842 U.S. Pat. No. 3,482,908 U.S. Pat. No. 2,101,979 U.S. Pat. No. 3,482,913 U.S. Pat. No. 2,111,445 U.S. Pat. No. 3,508,920 U.S. Pat. No. 2,114,060 U.S. Pat. No. 3,520,588 U.S. Pat. No. 2,157,099 U.S. Pat. No. 3,737,567 U.S. Pat. No. 2,194,737 U.S. Pat. No. 3,815,979 U.S. Pat. No. 2,375,962 U.S. Pat. No. 3,903,358 U.S. Pat. No. 2,478,891 U.S. Pat. No. 3,960,563 U.S. Pat. No. 2,566,700 U.S. Pat. No. 3,963,332 U.S. Pat. No. 2,627,200 U.S. Pat. No. 4,131,342 U.S. Pat. No. 2,727,427 Brit. 552,582 U.S. Pat. No. 2,729,427 Brit. 555,670 U.S. Pat. No. 2,792,745 ______________________________________
To my knowledge, no prior art methods or apparatus for producing three-dimensional motion pictures have gained any significant commercial acceptance. This is believed to be due to the expense and inconvenience of using or wearing the auxiliary equipment for visualization, and by a major problem of objectionable flicker, jump, or "keystoning" effect occurring in a projected scene due to the difficulty in accurately superimposing right and left views of the scene on a viewing surface.
As described in my aforesaid previously filed U.S. patent applications, I discovered that naturally occurring visual scenes could be recorded and projected onto a conventional two dimensional receiving surface for acceptable visualization in stereopsis by the unaided human eye by maintaining certain critical parameters in the process of recording and projection of the visual scene. More specifically, I found that naturally occurring visual scenes must be recorded from left and right camera lens positions, separated at a lateral distance of no more than about one inch. The recorded scenes must be projected onto a surface for visualization at an alternating right/left view duration, or film frame tempo rate, which is approximately equal to the visio-psychological alternation rate between right and left eye views of the human visual apparatus. This alternation rate of right and left eye views in the human brain which permits the mind to visualize a scene in stereopsis has been found to be from between about 1/24 to 1/4 of a second.
As also described in my aforesaid U.S. patent applications, I discovered that all moving objects in a scene to be recorded may be disregarded when establishing the control parameters of lateral lens base separation of the recording cameras and the film frame tempo (visual duration of left and right views), to provide acceptable visualization in stereopsis by the unaided human eye. More particularly, I discovered that the predominant point of consideration in establishing the aforementioned parameters is the nearest non-moving object in the visual scene to be recorded. By utilizing the nearest non-moving object in the natural scene as a reference point, precise variations within the aforementioned limits of lens base separation and film frame tempo can be established.
As also mentioned in my aforementioned patent applications, I found that stereopsis without objectionable flicker or keystoning effect could be further enhanced by maintaining a focus disparity between the right and left view recording cameras based on the distance to the nearest non-moving object in the scene. That is, by setting the central point of focus of the left and right recorded views of the scene at different selected distances relative to the nearest predominant non-moving object in the scene, flicker or jump between right and left views during projection is further diminished. Preferably, the central point of focus of one recording camera is set at a distance in front of the nearest non-moving object which is approximately one third of the distance of the object from the camera, while the central point of focus of the other camera is set at a distance behind, or beyond, the nearest non-moving object which is approximately one third more than the distance of the object from the recording camera.